1. Field of the Invention
The present invention relates to the field of plant breeding and, more specifically, to the development of Cucurbita pepo Halloween type pumpkin line HWN 130-1018T.
2. Description of Related Art
The goal of vegetable breeding is to combine various desirable traits in a single variety/hybrid. Such desirable traits may include greater yield, resistance to insects or pests, tolerance to heat and drought, better agronomic quality, higher nutritional value, growth rate and fruit properties.
Breeding techniques take advantage of a plant's method of pollination. There are two general methods of pollination: a plant self-pollinates if pollen from one flower is transferred to the same or another flower of the same plant or plant variety. A plant cross-pollinates if pollen comes to it from a flower of a different plant variety.
Plants that have been self-pollinated and selected for type over many generations become homozygous at almost all gene loci and produce a uniform population of true breeding progeny, a homozygous plant. A cross between two such homozygous plants of different varieties produces a uniform population of hybrid plants that are heterozygous for many gene loci. Conversely, a cross of two plants each heterozygous at a number of loci produces a population of hybrid plants that differ genetically and are not uniform. The resulting non-uniformity makes performance unpredictable.
The development of uniform varieties requires the development of homozygous inbred plants, the crossing of these inbred plants, and the evaluation of the crosses. Pedigree breeding and recurrent selection are examples of breeding methods that have been used to develop inbred plants from breeding populations. Those breeding methods combine the genetic backgrounds from two or more plants or various other broad-based sources into breeding pools from which new lines are developed by selfing and selection of desired phenotypes. The new lines are evaluated to determine which of those have commercial potential.
One crop species which has been subject to such breeding programs and is of particular value is the pumpkin. Pumpkin is one common name for members of the genus Cucurbita of the family Cucurbitaceae which are harvested as fully mature fruits. Cucurbita species include Cucurbita pepo, Cucurbita maxima, Cucurbita mixta, and Cucurbita moschata. In the United States, the thick-growing, small-fruited bush, or non-trailing varieties of C. pepo grown for immature fruit harvest are called summer squash or zucchini, and the long-season, long-trailing, large-fruited varieties are called pumpkin or winter squashes. Certain types of fruits often referred to as pumpkin are also found in C. moshata, C. maxima, and C. mixta. Regardless of species, “pumpkin” usually refers to the fruit of the genus Cucurbita. Halloween type pumpkins (exclusively Cucurbita pepo) can be used as a table vegetable or in pies, but are used most commonly used exclusively for autumn decoration. White, red, and gray varieties of pumpkin fruit are also available. Additionally, pumpkin seeds, either hulled or hull-less, can be roasted and consumed. Pumpkin seeds are a good source of iron and minerals.
Botanically, the fleshy, edible portion of the pumpkin is a fruit, but is conventionally considered a vegetable. The pumpkin fruit may be very large or small, but are typically grown to the mature stage. Pumpkins that are grown to maturity for use as Jack-o-lanterns or as pie ingredients often have a stringy coarse flesh that varies in color from orange to yellow to white. The stems of the genus Cucurbita usually help identify the species. For example, C. pepo and C. mixta have hard, five-angled stems, but C. moschata has a long, slender, columnar five-angled stem, and C. maxima has a soft, round stem. The leaves of Cucurbita are simple with 3-5 lobes.
Cucurbita plants generally have bright yellow monoecious flowers. Like stem morphology, peduncle morphology may help identify the different species. C. pepo typically have a 5-8 ridged peduncle with deep grooves; C. maxima typically have a cylindrical peduncle without any grooves; C. moschata and C. mixta typically have five-ridged peduncles that flare at the fruit attachment point, but the C. mixta peduncle is typically rounded and only slightly flared. All Cucurbita spp. typically have separate male and female flowers, requiring a pollinizer to enable fruit and seed development. Cross-pollination is possible between some pairs of the different Cucurbita species, though may be very difficult. Cucurbita spp. have spiny, sticky pollen that requires active pollinators. In the past, most pumpkins were pollinated by squash bees, but now most commercially grown pumpkins are pollinated by honeybees or hand pollinated.
C. pepo is a diploid species, with 2n=24 chromosomes. Most commercially grown pumpkins are F1 hybrids. Representative varieties include “Baby Boo” (white) and “Munchkin” which are both miniature C. pepo; “Prizewinner,” and “Big Moon,” which are both jumbo C. maxima; and “Magic Lantern,” “Jackpot,” “Autumn Gold,” and “Frosty.” “Small Sugar” and “Winter Luxury” are both representative cooking varieties of pumpkin.
Pumpkin is cultivated worldwide, though the Halloween type pumpkin is grown widely only in the U.S. and parts of Canada. In the U.S., the principal pumpkin growing states include Illinois, Ohio, California, Michigan, Pennsylvania, New York, and Texas, though they are produced in every state. Most pumpkin is direct seeded in tilled fields, but transplants are also used. No-till production is possible, but may be complicated by weed and disease problems. Fertilizer application to the beds is often required, and preferably is complete before planting. Pumpkin is a warm season crop that typically matures in 70-115 days depending on variety and environment; giant pumpkins and some tropically adapted pumpkins may require 150 days or more to mature.
While breeding efforts to date have provided a number of useful pumpkin lines with beneficial traits, there remains a great need in the art for new lines with further improved traits. Such plants would benefit farmers and consumers alike by improving crop yields and/or quality.